Powder-actuated tool



Oct 20, 1970 R. w. HENNING POWDER-ACTUTED TOOL n. G 1 @Ng m m m m W Q l nM Vl m, N@ m N R w wm N Nb QN* w l www Nl @Ng W x w x .S w l l l ii w. wm /w & \1\ Ww k d N; ww 5T swa ATTORNEY Oct. 20, 1970 R. w. HENNING POWDER-ACTUATED TOOL 2 SheetS-Sheet 2 Filed Aug.v 15, 1968 s Q @@fm ,.w 2 ,A l N l H w A l n Tlm @s @5% NN ROBERWHENN/NG 4 BY gw ATTORNEY United States Patent O 3,534,895 POWDER-ACTUATED TOOL Robert W. Henning, North Haven, Conn., assignor t Olin Corporation, a corporation of Virginia Filed Aug. 15, 1968, Ser. No. 752,951

Int. Cl. B25c 1/14 U.S. Cl. 227- 29 Claims ABSTRACT 0F THE DISCLOSURE A powder-actuated fastening tool capable of utilizing caseless ammunition. The tool includes a rotatable drum mounted iu a housing, said drum being provided with a cartridge receiving chamber which is rotatable from a loading position to a tiring position. A piston is provided having a tiring pin mounted on the rearward end thereof.

This invention relates generally to powder actuated tools.

More particularly, this invention relates to fastening tools of the piston type especially adapted to utilize a caseless pellet of gunpowder.

In designing tools to utilize a caseless pellet, several problems arise which would not normally arise in tools which utilize standard ammunition having a metal case. The provision of this case serves as a seal, since as the cartridge is fired, the case expands into sealing engagement with the cartridge receiving chamber and breech. When this case is eliminated, the problem of gas leakage becomes serious. In addition, the tool must be so designed that the caseless pellet receives enough force from the firing pin to properly ignite the caseless ammunition in a manner such that it will be properly consumed. In addition, from a practical standpoint some dirt and residue remain after the firing of a caseless pellet. Thus, cloging of various moving parts can become a problem.

In addition to the problem raised through the use of caseless ammunition, tools of the general type disclosed herein must also be constructed in a manner to prevent accidental or improper tiring. Moreover, tools of the type that utilize a piston to drive a fastener require some means of adjusting the power level other than by merely changing to a higher or lower powder charge.

In view of the above, it is an object of the present invention to provide a tool which can utilize caseless ammunition.

More particularly, it is an object of the present invention to provide a tool having a breech which is so designed that the tool can utilize caseless ammunition without excessive gas leakage.

Yet another object of this invention is to provide a tool capable of utilizing caseless ammunition and which tends to clean itself so that moving parts cannot become clogged. t

A further object of this invention is the provision of a powder-actuated tool of the piston type having a piston so constructed that various pistons can be manufactured economically to be interchanged with the piston in the tool to provide different power levels.

Still another object of the present invention is the provision of a powder-actuated tool having improved safety features to prevent ring unless the tool is properly positioned against the work surface and the operator is ready for the tiring operation.

Another object of the present invention is the provision of a piston assembly for use in a piston type powder-actuated tool which is so constructed that the operator can easily and relatively rapidly change the power level of the tool.

A still further object of this invention is to provide 3,534,895 Patented Oct. 20, 1970 Pme Y a tool wherein the muzzle bushing is adjustable to accommodate fasteners of a different length.

These and other objects and advantages of the present invention will become more apparent by reference to the following description of a preferred embodiment of the invention and to the accompanying drawings in which:

FIG. l is a vertical sectional view of the preferred embodiment of a tool constructed in accordance with the present invention;

FIG. 2 is a partial horizontal sectional view of the rearward portion of the tool;

FIG. 3 is a top plan view of the rearward portion of the tool;

FIG. 4 is a partial side elevation of the rearward portion of the tool;

FIG. 5 is a view similar to FIG. 2, but showing the components of the tool in a loading position;

FIG. 6 is a top plan view showing the handle in the position when the components of the tool are positioned as shown in FIGURE 5;

FIG. 7 is a view similar to FIGURE 2, but showing the components of the tool positioned in the safety position;

FIG. 8 is a top plan view showing the handle in its position when the components of the tool are positioned as shown in FIGURE 7; and

FIG. 9 is a view similar to FIGURE 2, but showing a second embodiment of the piston assembly.

Referring to the drawings, and in particular to FIG- URE l, the preferred embodiment of the tool comprises generally a housing assembly 2, a barrel assembly 4 attached to the housing assembly 2, a muzzle bushing assembly 6 operably connected for relative movement with respect to the barrel assembly 4, and a piston assembly 8 mounted within the barrel means for relative movement.

The housing assembly 2 includes a block-like housing member 10 machined from a suitable material such as steel or other metals. The forward end of the housing member 10 is provided with an internally threaded counterbore 12 having an axis which extends in the direction of the axis of the tool. A second counterbore 14 is provided in the housing member 10 with its axis extending in a direction perpendicular to the axis of the tool. The counterbore 14 extends a portion of the way through the housing member 1l) to a shoulder 1-6. A reduced bore 18 extends the remainder of the way through the housing member 10. The forwardmost surface of the counterbore 14 is spaced rearwardly from the bottom of the counterbore 12 to provide a breech face 20. The breech face 20 is provided with a port 22 having an axis coincident with the axis of the tool. For purposes of orientation throughout the remainder of the description of the tool, the tool will be considered as being positioned such that the main axis of the elongation of the tool is in a horizontal plane and the axes of the counterbore 14 and bore 18 lie in a vertical plane. It will, of course, be readily apparent that the tool can be used with its axis of elongation in a vertical or inclined plane depending upon the angle of the work pieces.

A cartridge receiving drum 24 is rotatably mounted within the counterbore 14 and reduced bore 18 in the housing member 10. The drum 24 is provided with a rst cylindrical outer surface 26 which is in tight, but rotatable, engagement with the surface of the counterbore 14, a bot'- tom shoulder 28 which engages the shoulder 16 formed by the counterbore 14, and a reduced, cylindrical portion 30 having an outer surface in engagement with the surface of the -bore 18. The end of portion 30 extends beyond the outer edge of the housing 2.

The top surface 32 of the drum 24 is flat. A plug 34 having a flat bottom surface 36 and external threads in engagement with the internal threads in the upper portion of the counterbore 14 has its bottom surface 36 in contact with the top surface 32 of the drum 24 to confine the drum 24 between the plug 34 and shoulder 16 formed by counterbore 14 and thereby prevent lateral movement. The cylindrical surface 26 of the drum 24 is provided with a cartridge receiving chamber 38 which is of sucient depth so that it can completely receive a pellet of caseless ammunition. When the tool is in the firing position as shown in FIG. 1, the cartridge receiving chamber 38 is in alignment with the port 22 in the breech face 20. When the tool is in the loading position such as shown in FIG. 5, the cartridge receiving chamber 38 is in communication with a loading port 40 in the rearward face of the housing 2. Preferably, the loading port 40 includes a funnel-shaped outer portion 42 and cylindrical bore 44 to facilitate the loading of a caseless pellet.

A series of two vertically extending grooves 46 are provided along the entire length of the cylindrical outer surface 26 of the drum 24 on either side of the cartridge receiving chamber 38. The grooves 46 create a turbulence if any of the gases generated by the detlagration of the cartridge tend to escape around the surface 26 of the drum 24 and help seal against further gas leakage. In addition, as the drum 24 is rotated about its axis from the firing position to the loading position, the edges of these grooves 46 tend to wipe the wall of the counterbore 14 to prevent the buildup of residue. To further prevent leakage, a circumferential groove 48 is provided in portion 30 of the drum.

The tip of portion 30 of the drum 24 is reduced to form a shoulder 50. A handle member 52 having a at portion 54 with an aperture 56 therein is mounted on the tip of portion 30 of the drum 24 such that the reduced portion thereof extends through the aperture 56 and the inside surface of the flat portion 54 immediately surrounding the aperture 56 bottoms against the shoulder 50. The handle member 52 may be secured to the drum 24 by any suitable method such as welding or the like.

The handle 52 includes a handle grip 58 extending along the side of the tool and being elongated in a direction of the axis of the tool. The handle grip 58 is connected to the flat portion 54 by means of an intermediate portion 60 which is bent at right angles around the corner of the housing member 10. A portion of the rearward end of the handle grip 58 is punched inwardly toward the housing 2 to provide a stop member 62. When the tool is in the firing position, the stop member 62 is received within an indentation 64 in the side of the housing 2 such that the inside edges of the grip 58 of the handle S2 can lay at along the side of the tool.

A portion of the llat portion 54 of the handle 52 is sheared inwardly toward the housing 2 to form a spring abutment surface 66. A spring member 68, shown in dotted lines in FIG. 3, is mounted in the space between the handle 52 and the housing 2 and has one end portion 70 abutting against the surface of the stop member 62 away from the grip 58 of the handle 52, is coiled twice about the axis of the drum 24 and has its other end 72 turned inwardly toward the housing 2, and mounted in a stop cavity therein to prevent movement thereof. The spring is coiled in such a manner and is constructed from a suitable material such that it tends to move the handle grip 58-from a position wherein the inside edges of the handle grip 58 are flush with the tool and the cartridge chamber 38 aligned with the port 22 in the breech face 20l to a point where the entire handle is rotated clockwise between and 35 as viewed in FIGS. 3 and 8.

A spacer member 74 is mounted in a counterbore 76 in the outer surface of the housing member 10 and is positioned between the bottom of that counterbore 76 and the inside surface of the at portion 54 of the handle 52. The spacer 74 prevents binding of the spring against the l portion 30 of the drum 24, when the handle 52 is moved toward the ring position.

The barrel assembly 4 includes a barrel member 78 having its rearward end provided with external threads and threadedly secured within the counterbore 12 in the housing 2. The main cylindrical bore 80 of the barrel member 78 is generally cylindrical and extends from the forward end thereof to a tapered shoulder 82 which tapers inwardly and rearwardly until it meets with a reduced cylindrical bore 84 which extends to the rearward end of the barrel member 78. The outer surface of the barrel member 78 adjacent the forward end is reduced to form a shoulder 86. The outer surface immediately rearward of the shoulder 86 is externally threaded as indicated at 88 and is in engagement with the internal threads 90 of a cap member 92. The cap member 92 is a generally cylindrical internal surface 94 with its forward end having an inturned ilange 95 forming an internal stop shoulder 96. A grip 97, fabricated from rubber, plastic, or other suitable material Surrounds the barrel member 78 and extends from the rearward face of the cam member 92 to the forward face of the housing member 10.

The muzzle bushing assembly 6 includes an internally threaded nut 98 mounted within the cap member 92. The nut 98 includes a generally cylindrical forward portion 99, a cylindrical rearward surface 100, and an outwardly extending flange 102 between said surfaces which forms a forward abutment surface 104 and a rearward abutment surface 106. A muzzle bushing spring 108 is undercompression between the abutment surface 106 of the nut 98 and the shoulder 86 of the barrel member 78 and urges the nut 98 forwardly so that the abutment surface 104 is in engagement with the abutment shoulder 96 of the cap 92 with a portion of the forward portion 99 of the nut 98 extending forwardly from the cap member 92. A muzzle bushing member 110, of generally cylindrical construction with a bore therethrough, has its outer surface threaded as indicated by the numeral 112 from its rearward end substantially the entire length thereof. The muzzle bushing is threadedly received within the nut 98 and is adjustable along the axis of the tool relative to the barrel member 78. A set screw 114 or other frictional holding means is provided in the nut 9S for securing the muzzle bushing in its desired location. Access to the set screw may be had through an opening 116 in the cap 92. A buffer plate 118 having a bore 120, a counterbore 122, and a flat rearward surface 123, is press t onto the muzzle bushing 110. The buffer plate 118 has an outside diameter slightly less than the internal diameter of the bore 80 of the barrel member 78.

The piston assembly 8 includes a piston body 124 having a threaded head portion 126 at its rearward end. The main portion of the piston body 124 has an external diameter substantially equal to the internal diameter of the muzzle bushing 110. A piston head 128 is threadedly attached to the head portion 126 of the piston body 124 by means of an internally threaded counterbore 130 in its forward end. The piston head 128 also includes a reduced bore 132 extending from the counterbore through the rearward end of the piston head 128. The bore 132 is in axial alignment with the port 22 in the breech face 20 and also forms along with the counterbore 130 an internal shoulder 134 within the piston head 128. The piston head 128 also has a circular flange 136 extending outwardly at a point adjacent its forward end and having a diameter substantially equal to the internal diameter of the main bore 80 of the barrel member 78. The piston head 128 has its intermediate external surface reduced as indicated by numeral 138 and also includes a rearward portion 140 having a larger diameter than the reduced portion 138. The diameter of the portion 140 is substantially equal to the diameter of the reduced bore 84 of the barrel member 78.

A ring pin 142 is mounted in the piston head 128 and includes a reduced rod portion 144 extending through the reduced bore 128 thereof and a head portion 146 having a forward shoulder 148 in engagement with the internal shoulder 134 of the piston head 128. A spring member 150 surrounds the reduced portion 138 of the piston head 128 and extneds between the shoulder 82 in the barrel member 78 and the rearward face of the ange 136 to urge the piston assembly 8 slightly forwardly inthe tool. The provision of the spring member 150 prevents air firing of the tool since it acts against the inertia of the piston assembly 8 if the tool was in the yfiring position and the rearward face of the housing member 10 hit with a suitable implement.

A cyindrical buffer member 152 is mounted with a friction t on the piston body 124 forward of the threaded head portion 126. The buffer member 152 may be fabricated from any suitable material such as nylon, polyure thane, or other elastomeric materials. The buffer prevents damage to the tool in the event of an overdrive of the piston. If such an event happens, the buffer member 152 will be driven against the flat rear surface 123 of the plate 118 and absorb the excess energy and prevent metal-to metal contact of metallic parts of the piston assembly 8 with the muzzle bushing assembly 6.

In assemblying the piston assembly 8, the ring pin 142 is mounted within the piston head 128 and the piston head 128 then screwed onto the threaded head portion 126 of the piston body 124 so that the head 146 of the firing pin 142 is securely held between the rearward face of the head 126 of the piston body 124 and the shoulder 134 in the piston head 128. By virtue of this construction, a manufacturer can construct a plurality of different piston assemblies to provide different power levels for a given load with relatively little expense, since the manufacturer can use the same piston body and buffer member in all cases and change only the length of the firing pin, length of the piston head, or both, to provide a change in the volume of the cavity 154 immediately forward of the port 22 when the firing pin has moved to its rearwardmost position and detonated the cartridge. By changing the volume, the power level of the tool is changed. The larger the initial volume of the cavity 154, the lower the power level and vice versa.

In the alternative embodiment shown in FIG. 9, the piston body or shank 156, piston head 158, and tiring pin 160 may be made as a solid piece. Power adjustment may then be accomplished by means of a plurality of removable washers. As shown in FIG. `9, in the preferred form there are two such washers 162 and 164, each having an aperture 166 through which the firing pin 160 extends and an outside diameter of such a dimension as to be in sliding engagement with the reduced bore 84 of the barrel member 78. This arrangement permits the operator of the tool to change the power level merely by removing one or both of washers 162 and 164. With both washers 162 and 164 mounted on the firing pin, the volume of the cavity 168 immediately forward of the port 22 when the firing pin has moved to its rearwardmost position and detonated cartridge will be the smallest. Thus, in this case, the tool will have its highest power level for a given load. If one washer 164 is removed, an intermediate power level will result. The removal of both washers 162 and 164 results in the cavity 168 having its largest volume at firing, and thus, the lowest power level.

Prior to the firing operation, the operator should adjust the muzzle bushing 110 for the particular length fastener to be driven. To do this, the handle 52 is rotated so as to move the cartridge chamber 38 out of alignment with the port 22 and firing pin 142. A fastener 170 is then inserted in the muzzle bushing 110 and pushed rearwardly in the tool until it engages the piston member. The set screw 114 of the nut 98 is loosened and the muzzle bushing 110 is then rotated in the proper direction with respect to the nut 98 so that the forward face of the muzzle bushing 110 moves axially to a point where it is sub- 6 stantially Hush with the tip of the fastener 156. The set screw 114 is then retghtened to prevent any relative rotation between the muzzle bushing and nut 98.

In operation, to load a caseless pellet or other suitable cartridge, the handle 52 is rotated toward the rear of the tool in a clockwise direction as viewed in FIG. 6, until the stop member 62 thereof abuts the rearward surface of the housing 2. At this point, the cartridge receiving chamber 38 is in alignment with the loading port 40 whereby the appropriate cartridge can be dropped into place. The handle 52 is then rotated in the opposite direction 180 whereupon the operator must hold the handle grip 58 in abutment with the side of the tool as shown in FIGS. 2 and 3. When the handle is in this position, the cartridge chamber is in alignment with the port 22 and firing pin 142 and the tool is ready for tiring.

A special feature of this tool is that it may be fired in two different ways. If the exact location of the fastener in the work piece is not important, the operator may merely slam the forward end of the muzzle bushing 110 against the work piece. In so doing, the barrel assembly 4 and housing assembly 2 moves forwardly relative to the muzzle bushing assembly 6 and piston assembly 8 causing the cartridge in the cartridge receiving chamber 38 to impinge upon the rearward end of the tiring pin 142 resulting in deilagration of the cartridge. The gases generated by the deilagration of the cartridge will drive the piston body 124 forward which in turn drives the fastener 156 into the work piece.

If the location of the fastener is important, the operator can first position the forward end of the muzzle bushing 110 in the proper location and then rap the rearward face of the housing member 10 with a suitable instrument such as a hammer or the like, whereupon the housing assembly 2 and barrel assembly 4 will move forward relative to the muzzle bushing assembly 6 and piston assembly 8 and deagrate the cartridge in the cartridge chamber 38 in the manner described above.

By virtue of the spring 68, if the operator does not grasp the handle grip 58 and hold it against the tool, the handle 52 will tend to rotate clockwise from its position as shown in FIG. 3 toits position shown in FIG. 8. This in turn causes the drum 24 to rotate resulting in the cartridge receiving chamber 38 being moved out of alignment with the firing pin 142 whereupon even if the tool was positioned against the work surface and the rearward surface of the housing 2 hit with a suitable instrument, the cartridge will not be deflagrated, providing a safety feature.

Although reference has been made above to specific embodiments of the present invention, it will be obvious that other alterations and modifications will readily suggest themselves to those skilled in the art. Accordingly, it is intended that the scope of this invention be ascertained from the following claims.

What is claimed is:

1. A powder-actuated tool comprising housing means, barrel means attached to said housing means, piston means mounted in said barrel means for reciprocal movement between a firing position and a fired position, a cartridge re ceiving member mounted in said housing and having a cartridge receiving chamber therein, a loading port in said housing, ring pin means extending from the rearward end of said piston means, and means movably mounting said cartridge receiving member for movement between a loading position wherein said cartridge receiving chamber is in communication with said loading port and a tiring position wherein said cartridge receiving chamber is in alignment with said tiring means.

2. The powder-actuated tool of claim 1 wherein said cartridge receiving member includes a cylindrical drum and is mounted in said housing for pivotal movement about its axis, said axis being perpendicular to the axis of said barrel means.

3. The powder-actuated tool of claim 2 wherein said loading port in said housing is spaced diametrically across said drum from said firing pin means.

4. The powder-actuated tool of claim 3 wherein said housing includes a breech face positioned between said drum and the interior of said barrel means, said breech face having a port therein, said port being in alignment with said firing pin means.

5. The powder-actuated tool of claim 1 wherein said housing means includes a cylindrical counterbore extending a portion of the way therethrough and a reduced bore extending from said counterbore the remainder of the way therethrough, the axis of said bore and counterbore being perpendicular to the axis of said barrel means, said counterbore and said reduced bore being separated by an internal shoulder, said cartridge receiving member including a first portion having cylindrical surface in sliding engagement with a portion of the wall of said counterbore and a reduced extension portion having a cylindrical surface extending from said rst portion of the direction of the axis of said reduced bore with the cylindrical surface thereof in engagement with the walls of said reduced bore, said cartridge receiving chamber being positioned in said first position, said first and second portions having a shoulder at the juncture thereof, said shoulder on said cartridge receiving member being in engagement with said internal shoulder, a plug member positioned in said cylindrical counterbore and secured thereto, said cartridge receiving member beingv confined in said housing means in the direction of the axis of said counterbore between said plug and said internal shoulder.

6. The powder-actuated tool of claim 5 wherein said reduced portion of said cartridge receiving member extends outside of said housing means, said tool further including a handle member attached to that portion of said reduced portion that extends outside of said housing means.

7. The powder-actuated tool of claim 5 wherein said lirst portion has a set of grooves extending axially in the outer surface thereof, there being at least one groove on either side of said cartridge receiving chamber.

8. The powder-actuated tool of claim 1 further including muzzle bushing means operably connected to said barrel means, said muzzle bushing means having a bore therein adapted to receive a fastener, and means mounting said muzzle bushing means for relative axial movement with respect to said barrel means.

9. The powder-actuated tool of claim 8 wherein said muzzle bushing means extends forwardly from said barrel means, and further including stop means for engagement by said muzzle bushing means to limit the forward movement of said muzzle bushing means relative to said barrel means, said piston means including a driving portion extending into the bore of said muzzle bushing, and means for adjusting the amount said muzzle bushing means extends from said barrel means when said muzzle bushing means is in engagement with said stop means.

10. The powder-actuated tool of claim 9 wherein said muzzle bushing means includes a nut member having an internally threaded bore and a muzzle bushing member having an external surface which is threaded along at least a portion of its length, said nut member being threadedly received on said muzzle bushing member, said barrel means having an inturned flange thereon forming said stop means, said nut member being received within said barrel means and having a ange to engage said inturned flange to limit forward movement of said muzzle bushing means with respect to said barrel means, and means in said nut member to releasably engage said muzzle bushing member to prevent relative rotation therebetween.

11. The powder-actuated tool of claim 10 wherein said barrel means includes a barrel member having a shoulder on its external surfaces at a point near its forward end and external threads along a portion of its external surface immediately rearward of said shoulder, and a hollow cap member having the rearward portion of its internal surface threadedly connected to said external threads of said barrel member, the forward end of said cap member being provided with said inturned flange, said means for urging said muzzle bushing means into engagement with said stop means including a spring member positioned between said shoulder in said barrel member and the rearward face of said ange on said nut.

12. The powder-actuated tool of claim 9 wherein said piston means includes a driving portion and an enlarged head portion, and further including a buffer plate attached to the rearward end of said muzzle bushing means and a non-metallic buffer member mounted on the driving portion of said piston means.

13. The powder-actuated tool of claim 8 further including means for resiliently holding said re pin means at a point spaced from said cartridge receiving chamber, said resilient means adapted to be compressed to permit the ring pin means to move toward said cartridge receiving chamber for tiring said tool.

14. The powder-actuated tool of claim 4, further including a handle member secured to said drum to provide means for rotating said drum, said handle member having a portion movable between a firing position wherein said portion is in engagement with the outer surface of said tool when said cartridge receiving chamber is in the ring position to a loading position wherein said cartridge receiving chamber is in said loading position.

15. The powder-actuated tool of claim 14, further including means for biasing said drum from a position wherein the cartridge receiving chamber is in the firing position to a point wherein said cartridge receiving chamber is out of said tiring position.

16. The powder-actuated tool of claim 15 where said means for biasing said drum includes a spring member, said handle having a spring abutment surface thereon, said housing having a spring stop cavity therein, said spring member being coiled about the axis of said drum with one end portion thereof in engagement with said spring abutment surface and the other end portion thereof being mounted in said stop cavity.

17. The powder-actuated tool of claim 16 wherein a portion of said drum protrudes from said housing, said handle member being attached to said protruding portion, and further including a spacer member mounted in a counterbore in said housing immediately surrounding said protruding portion, coils of said spring member being outside the circumference of said spacer member.

18. The powder-actuated tool of claim 14, further including stop means on said handle to stop the movement of the handle at the loading position as the handle is moved from the firing position to the loading position.

19. A powder-actuated tool including housing means, barrel means attached to said housing means, piston means mounted in said barrel means for reciprocal movement between a ring position and a fired position, a cartridge receiving chamber and firing pin means, one of said chamber or :tiring pin means being movable with said piston means and the other being stationary with respect to said housing means during the firing of said tool, muzzle bushing means Operably connected to said barrel means and extending forwardly therefrom, means mounting said muzzle bushing means for relative axial movement with respect to said barrel means, stop means for engagement by said muzzle bushing means to limit forward movement of said muzzle bushing means, means urging said muzzle bushing means forwardly into engagement with said stop means, said piston means including a driving portion extending into the bore of said muzzle bushing, and means for adjusting the amount said muzzle bushing means extends from said barrel means when said muzzle bushing means is in engagement with said stop means.

20. The powder-actuated tool of claim 19 wherein said muzzle bushing means includes a nut member having an internally threaded bore and a muzzle bushing member having an external surface which is threaded along at least a portion of its length, said nut member being threadedly received on said muzzle bushing member, said barrel means having an inturned ange thereon forming said stop means, said nut member being received within said barrel means and having a ange to engage said inturned ilange to limit forward movement of said muzzle bushing means with respect to said barrel means, and means in said nut member to releasably engage said muzzle bushing member to prevent relative rotation therebetween.

21. The powder-actuated tool of claim 20 wherein said barrel means includes a barrel member having a shoulder on its external surfaces at a point near its forward end and external threads along a portion of its external surface immediately rearward of said shoulder, and a hollow cap member having the rearward portion of its internal surface threadedly connected to said external threads of said barrel member, the forward end of said cap member being provided with said inturned iiange, said means for urging said muzzle bushing means into engagement with said stop means including a spring member positioned between said shoulder in said barrel member and the rearward face of said ange on said nut.

22. The powder-actuated tool of claim 1 wherein said piston means includes a piston body, a piston head having at least a portion of its outside surface in engagement with the bore of said barrel means, said piston head having a rst bore in its forward end, a second reduced bore extending through its rearward end, and an intermediate stop shoulder therein, said firing pin means including an enlarged head portion and a reduced rod portion, said firing pin means being mounted in said piston head with the enlarged head portion thereof in engagement with said stop shoulder and the rod portion extending through said reduced bore, the rearward end portion of said piston body being secured within said rst bore and in engagement with the head of said -ring pin means to retain said ring pin head in an axial direction between said head of said piston body and said stop shoulder.

23. The powder-actuated tool of claim 1 wherein said piston means includes a shank portion, and an enlarged head portion at the rearward end of said shank portion, said tiring pin means extending rearwardly from said shank portion, said tiring pin means including a rod-like portion, and at least one removable washer member mounted on said rod-like portion and having an outside diameter the same as the diameter of the adjacent head portion.

24. A piston for use in a powder-actuated tool, said piston including a piston body, a piston head having a iirst bore in its forward end and a second reduced bore extending through its rearward end, an intermediate stop shoulder in the internal surface of said head portion between said tirst and second bores, tiring pin means including an enlarged head portion and a reduced rod portion, said tiring pin means being mounted in said piston head with the enlarged head portion in engagement with said stop shoulder and said rod portion extending through said reduced bore, the rearward end portion of said piston body being secured within said rst bore and in engagement with the head of said ring pin means to retain said ring pin means in a direction along the axis of elongation of said piston body between said head of said piston body and said stop shoulder.

25. The powder-actuated tool of claim 7 further including grooves extending about the surface of that portion of said reduced portion that is contained Within said housing means.

26. A powder-actuated tool comprising housing means, barrel means attached to said housing means, piston means mounted in said barrel means for reciprocal movement between a ring position and a tired position, a cartridge receiving member mounted in said housing and having a cartridge receiving chamber therein, a loading port in said housing, tiring pin means extending from the rearward end of said piston means, means movably mounting said cartridge receiving member for movement between a loading position wherein said cartridge receiving chamber is in communication with said loading port and a ring position wherein said cartridge receiving chamber is in communication with said barrel, handle means secured to said cartridge receiving member for moving said cartridge receiving member between said loading position and said tiring position, and means for stopping the movement of said cartridge receiving member in the tiring position as it is moved from said loading position to said tiring position.

27. The powder-actuated tool of claim 26 further including means biasing said cartridge receiving member out of said firing position unless said handle is held to maintain said cartridge receiving member in said ring position.

28. A powder-actuated fastening tool comprising a housing having a loading port therein, a barrel member attached to said housing, a cartridge receiving member mounted in said housing and having a cartridge receiving chamber therein, handle means attached to said cartridge receiving member for moving said cartridge receiving member from a loading position wherein said cartridge receiving chamber is in communication with said loading port for the insertion of a powder charge into said cartridge receiving chamber to a firing position wherein said cartridge receiving chamber is in communication with said barrel member, tiring pin means for actuating a powder charge when said cartridge receiving member is in said tiring position, means for stopping the movement of said cartridge receiving member in said firing position as it is moved from said loading position to said tiring position, and means biasing said cartridge receiving member out of said tiring position unless said handle means is held to maintain said cartridge receiving member in said tiring position.

29. A powder-actuated fastening tool comprising a housing, a loading port in said housing, a barrel member attached to said housing, a piston member mounted for reciprocal movement in said barrel member, a cartridge receiving member having a cartridge receiving chamber therein, means mounting said cartridge receiving member in said housing for movement between a loading position wherein said cartridge receiving member is in communication with said loading port and a ring position lwherein said chamber is in communication with said loading port for the insertion of a powder charge into said cartridge receiving chamber and a tiring position wherein said chamber is in communication with said barrel, and tiring pin means for actuating the powder charge when said cartridge receiving member is in said tiring position.

References Cited UNITED STATES PATENTS 3,395,843 8/1968 Kuavle 227-10 3,415,438 12/1968 De Caro 227-10 3,469,757 9/1969 Kuavle et al. 227-10 GRANVILLE Y. CUSTER, JR., Primary Examiner UNITED STTES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,534,895 Dated october 2o, 1970 Inventor(s) Robert W. Henning It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 5, line 12 "of" (first occurrence) should read in;

Claim 5, line 16, "position" should read "portion".

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